Electrolytic solution for non-aqueous electrolyte battery and non-aqueous electrolyte battery using the same

ABSTRACT

An electrolytic solution for a non-aqueous electrolyte battery is provided, which is capable of providing an excellent low-temperature output characteristic at −30° C. or lower and an excellent cycle characteristic at high temperatures of 45° C. or higher. For example, the electrolytic solution contains the following salt having a divalent imide anion. 
     
       
         
         
             
             
         
       
     
     wherein R 1  to R 3  represent a fluorine atom or an alkoxy group, for example, and M 1  and M 2  represent protons or metal cations, for example.

TECHNICAL FIELD

The present invention relates to an electrolytic solution to be used fora non-aqueous electrolyte secondary battery excellent in a cyclecharacteristic and a low-temperature characteristic, as well as anon-aqueous electrolyte battery using the same.

BACKGROUND ART

In recent years, power storage systems to be applied for smallapparatuses that need high energy density, such as informationtechnology-related apparatuses or communication apparatuses,specifically, personal computers, video cameras, digital still cameras,and cell phones, and power storage systems to be applied for largeapparatuses that need power, such as electric vehicles, hybrid vehicles,auxiliary power for fuel cell vehicles, and energy storage have receivedattention. As a candidate therefor, non-aqueous electrolyte batteriessuch as a lithium ion battery, a lithium battery, a lithium ioncapacitor, or a sodium ion battery, have been actively developed.

Many of these non-aqueous electrolyte batteries have already been putinto practical use, however, none of these batteries are sufficient forvarious applications in terms of respective characteristics. Inparticular, a battery to be applied for a vehicle such as an electricvehicle is required to have a high input output characteristic even in acold season. Hence, improvement in a low-temperature characteristic isimportant. Moreover, such a battery is required to have ahigh-temperature cycle characteristic such that it is capable ofmaintaining its characteristics (less increase in internal resistance)even when charging and discharging are performed repeatedly under ahigh-temperature environment.

As a means for improving the high-temperature characteristic, and thebattery characteristics (a cycle characteristic) wherein charging anddischarging are repeated, optimization of various battery componentsincluding active materials of positive electrodes and negativeelectrodes has been studied. A non-aqueous electrolytic solution-relatedtechnology is not an exception, and it has been proposed thatdeterioration due to decomposition of an electrolytic solution on thesurface of an active positive electrode or an active negative electrodeis suppressed by various additives. For example, Patent Document 1proposes that battery characteristics are improved by the addition of avinylene carbonate to an electrolytic solution. However, this isproblematic in that battery characteristics at high temperatures areimproved, but the internal resistance is significantly increased tolower the low-temperature characteristic. Furthermore, a number ofexaminations on the addition of an imide salt to an electrolyticsolution have been conducted. For example, there have been proposed amethod (Patent Document 2) for suppressing deterioration in ahigh-temperature cycle characteristic or a high-temperature storagecharacteristic by combining a specific sulfonimide salt or a phosphorylimide salt with an oxalato complex, and a method (Patent Document 3) forsuppressing deterioration in a cycle characteristic or an outputcharacteristic by combining a specific sulfonimide salt with afluorophosphate.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP Patent Publication (Kokai) No. 2000-123867A

Patent Document 2: JP Patent Publication (Kokai) No. 2013-051122A

Patent Document 3: JP Patent Publication (Kokai) No. 2013-030465A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

A low-temperature characteristic and a high-temperature cyclecharacteristic provided by non-aqueous electrolyte batteries usingnon-aqueous electrolytic solutions disclosed in the prior art documentsare not completely satisfactory and still remain to be improved. Thepresent invention provides an electrolytic solution to be used for anon-aqueous electrolyte battery capable of providing a goodlow-temperature output characteristic at −30° C. or lower and a goodcycle characteristic at high temperatures of 45° C. or higher, as wellas a non-aqueous electrolyte battery using the same.

Means for Solving the Problems

Intensive studies have been made in order to solve the problems, and asa result, the present inventors have discovered that a non-aqueouselectrolyte battery can provide a good low-temperature outputcharacteristic and a high-temperature cycle characteristic, byintroducing a specific salt having a divalent imide anion with aspecific structure into a non-aqueous electrolytic solution to be usedfor a non-aqueous electrolyte battery comprising a non-aqueous solventand a solute contains and then using the resultant non-aqueouselectrolyte in the non-aqueous electrolyte battery. Based on thisfinding, the present invention has been completed.

Specifically, the present invention provides an electrolytic solution tobe used for a non-aqueous electrolyte battery (hereafter, also referredto as simply “non-aqueous electrolytic solution” or “electrolyticsolution”) comprising a non-aqueous solvent, a solute, and at least onetype of salt having a divalent imide anion (hereafter, also referred toas simply “salt having an imide anion”) represented by any one of thefollowing general formulae (1) to (4).

wherein, in formulae (1) to (3), R¹ to R³ each independently represent afluorine atom or an organic group selected from a linear or branchedC1-10 alkoxy group, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group,a C3-10 cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10aryloxy group, wherein a fluorine atom, an oxygen atom or an unsaturatedbond may also be present in the organic group;

in formulae (2) and (4), X represents a fluorine atom or an organicgroup selected from a linear or branched C1-10 alkyl group, a C2-10alkenyl group, a C2-10 alkynyl group, a C3-10 cycloalkyl group, a C3-10cycloalkenyl group, a C6-10 aryl group, a linear or branched C1-10alkoxy group, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group, aC3-10 cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10aryloxy group, wherein a fluorine atom, an oxygen atom, or anunsaturated bond may also be present in the organic group; and

M¹ and M² each independently represent a proton, a metal cation or anonium cation.

The action mechanism for improving battery characteristics in accordancewith the present invention is not clearly understood. However, it isconsidered that a salt having an imide anion of the present invention ispartially decomposed at the boundary between a positive electrode and anelectrolytic solution, and the boundary between a negative electrode andthe electrolytic solution, so as to forma film. The film prevents thedecomposition of a non-aqueous solvent or a solute by inhibiting adirect contact between the non-aqueous solvent or the solute with anactive material, so as to suppress the deterioration of the batteryperformances. While the mechanism thereof is unclear, it is importantthat an imide anion has a phosphate ion site (—P(═O)R³O⁻) or a sulfonateion site (—SO₃ ⁻). It is considered that incorporation of a phosphateion site or a sulfonate ion site into the above film results in unevendistribution of electric charge of the thus formed film, which leads toa high lithium conductivity; that is, a low resistance (film having agood output characteristic). Furthermore, the above effect is consideredto be that an imide anion contains a site with a highelectron-withdrawing property (e.g., a fluorine atom and afluorine-containing alkoxy group) to further increase the degree ofuneven distribution of electric charge, so as to form a film with alower resistance (film having a better output characteristic). For thisreason, it is assumed that an effect of improving a high-temperaturecycle characteristic and a low-temperature output characteristic isexerted by the non-aqueous electrolytic solution containing a salthaving an imide anion according to the present invention.

The salt having an imide anion preferably has at least one P—F bond orS—F bond, in order to have a better low-temperature characteristic. Thesalt further preferably has as many P—F bonds or S—F bonds as possible,since the higher the number of P—F bonds or S—F bonds in the salt, themore the low-temperature characteristic can be improved.

It is preferable that the above R¹ to R³ are a fluorine atom or anorganic group selected from the group consisting of a C2-10 alkenyloxygroup and a C2-10 alkynyloxy group, in order to obtain a betterhigh-temperature cycle characteristic.

Furthermore, the number of carbons of the above alkenyloxy group ispreferably 6 or less. The higher number of carbons tends to provide arelatively higher internal resistance when a film is formed on anelectrode. The number of carbons is preferably 6 or less because theresulting internal resistance tends to be low. The alkenyloxy group isparticularly preferably selected from the group consisting of a1-propenyloxy group, a 2-propenyloxy group, and a 3-butenyloxy group inorder to obtain a non-aqueous electrolyte battery excellent in ahigh-temperature cycle characteristic and a low-temperature outputcharacteristic.

Furthermore, the number of carbons of the above alkynyloxy group ispreferably 6 or less. The higher number of carbons tends to provide arelatively high internal resistance when a film is formed on anelectrode. The number of carbons is preferably 6 or less, because theresulting internal resistance tends to be low. The alkynyloxy group isparticularly preferably selected from the group consisting of a2-propynyloxy group, and 1,1-dimethyl-2-propynyloxy group in order toobtain a non-aqueous electrolyte battery excellent in a high-temperaturecycle characteristic and a low-temperature output characteristic.

The above X is preferably a fluorine atom or an organic group selectedfrom the group consisting of a C1-10 alkoxy group, a C2-10 alkenyloxygroup, and a C2-10 alkynyloxy group in order to obtain a betterhigh-temperature cycle characteristic.

The number of carbons of the above alkoxy group is preferably 6 or less.The higher number of carbons tends to provide a relatively high internalresistance when a film is formed on an electrode. The number of carbonsis preferably 6 or less, because the resulting internal resistance tendsto be low. The alkoxy group is particularly preferably selected from thegroup consisting of a methoxy group, an ethoxy group, and a propoxygroup in order to obtain a non-aqueous electrolyte battery excellent ina high-temperature cycle characteristic and a low-temperature outputcharacteristic.

The number of carbons of the above alkenyloxy group is preferably 6 orless. The higher number of carbons tends to provide a relatively highinternal resistance when a film is formed on an electrode. The number ofcarbons is preferably 6 or less, because the resulting internalresistance tends to be low. The alkenyloxy group is particularlypreferably selected from the group consisting of a 1-propenyloxy group,a 2-propenyloxy group, and a 3-butenyloxy group in order to obtain anon-aqueous electrolyte battery excellent in a high-temperature cyclecharacteristic and a low-temperature output characteristic.

The number of carbons of alkynyloxy group is preferably 6 or less. Thehigh number of carbons tends to provide a relatively high internalresistance when a film is formed on an electrode. The number of carbonsis preferably 6 or less because the resulting internal resistance tendsto be low. The alkynyloxy group is particularly preferably selected fromthe group consisting of a 2-propynyloxy group and a1,1-dimethyl-2-propynyloxy group in order to obtain a non-aqueouselectrolyte battery excellent in a high-temperature cycle characteristicand a low-temperature output characteristic.

Counter cations M¹ and M² of an imide anion in the above salt preferablyrepresent protons, alkali metal cations, or onium cations. Of these, inview of solubility and ion electric conductivity in a non-aqueouselectrolytic solution, a counter cation is more preferably at least onecation selected from the group consisting of a proton, a lithium ion, asodium ion, a potassium ion, a tetraalkylammonium ion, and atetraalkylphosphonium ion.

The lower limit of the concentration of the salt is preferably 0.01 mass% or more, more preferably 0.05 mass % or more, and further morepreferably 0.1 mass % or more relative to the total amount of anelectrolytic solution for a non-aqueous electrolyte battery.Furthermore, the upper limit of the concentration is preferably 5.0 mass% or less, more preferably 4.0 mass % or less, and further morepreferably 3.0 mass % or less. The concentration that is lower than 0.01mass % makes it difficult to sufficiently obtain an effect of improvingbattery characteristics, so that such a concentration is not preferred.On the other hand, the concentration of higher than 5.0 mass % does notimprove the effect further and thus is not only useless, but also suchconcentration tends to increase the viscosity of the electrolyticsolution and decrease the ionic conductance, which leads to easilyincrease the resistance and deteriorate the battery performance, andthus is not preferred. These salts may be used singly as long as itsconcentration does not exceed 5.0 mass %, or they can be used as acombination of two or more kinds of the salts at any ratio, depending onapplications.

The above solute is preferably at least one solute selected from thegroup consisting of LiPF₆, LiPF₂(C₂O₄)₂, LiPF₄(C₂O₄), LiP(C₂O₄)₃,LiBF₂(C₂O₄) LiB(C₂O₄)₂, LiPO₂F₂, LiN(F₂PO)₂, LiN(FSO₂)₂, LiN(CF₃SO₂)₂,LiBF₄, NaPF₆, NaPF₂(C₂O₄)₂, NaPF₄(C₂O₄), NaP(C₂O₄)₃, NaBF₂(C₂O₄),NaB(C₂O₄)₂, NaPO₂F₂, NaN(F₂PO)₂, NaN(FSO₂)₂, NaN(CF₃SO₂)₂, and NaBF₄.

The above non-aqueous solvent is preferably at least one solventselected from the group consisting of a cyclic carbonate, a linearcarbonate, a cyclic ester, a linear ester, a cyclic ether, a linearether, a sulfone compound, a sulfoxide compound, and an ionic liquid.

The present invention further provides a non-aqueous electrolyte batterycomprising at least a positive electrode, a negative electrode, and theabove electrolytic solution for a non-aqueous electrolyte battery.

Effect of the Invention

When the present electrolytic solution is used for a non-aqueouselectrolyte battery, the resultant battery can exert a goodlow-temperature output characteristic at −30° C. or lower and a goodcycle characteristic at high temperatures of 45° C. or higher.

MODES FOR CARRYING OUT THE INVENTION

The present invention will be explained in detail as follows. However,explanations for constituent features described below are merelyexamples of the embodiments of the present invention, and the presentinvention is not limited to these specific contents and may be variouslymodified within the disclosure of the present specification.

The present electrolytic solution is an electrolytic solution for anon-aqueous electrolyte battery characterized by comprising anon-aqueous solvent, a solute, and at least one salt having a divalentimide anion, which is represented by any one of the general formulae (1)to (4).

In formulae (1) to (3), R¹ to R³ each independently represent a fluorineatom or an organic group selected from a linear or branched C1-10 alkoxygroup, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group, a C3-10cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10 aryloxygroup, wherein a fluorine atom, an oxygen atom, or an unsaturated bondmay be present in the organic group.

In formulae (2) and (4), X represents a fluorine atom or an organicgroup selected from a linear or branched C1-10 alkyl group, a C2-10alkenyl group, a C2-10 alkynyl group, a C3-10 cycloalkyl group, a C3-10cycloalkenyl group, a C6-10 aryl group, a linear or branched C1-10alkoxy groups, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group, aC3-10 cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10aryloxy group, wherein a fluorine atom, an oxygen atom or an unsaturatedbond may be also present in the organic group.

M¹ and M² as counter cations each independently represent a proton, ametal cation or an onium cation.

Examples of the counter cation include a proton, alkali metal cationssuch as a lithium ion, a sodium ion, and a potassium ion, alkaline earthmetal cations such as a magnesium ion and a calcium ion, onium cationssuch as tetramethyl ammonium, tetraethyl ammonium, andtetrabutylphosphonium (when counter cations are monovalent cations, 2kinds of the counter cations may be mixed. Moreover, for example, if M¹is a divalent cation, M² does not exist).

In the above formulae (1) to (3), examples of those represented by R¹ toR³, specifically: examples of alkoxy groups include C1-10 alkoxy groupsand fluorine-containing alkoxy groups such as a methoxy group, an ethoxygroup, a propoxy group, an isopropoxy group, a butoxy group, a secondarybutoxy group, a tertiary butoxy group, a pentyloxy group, atrifluoromethoxy group, a 2,2-difluoroethoxy group, a2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropoxy group and a1,1,1,3,3,3-hexafluoroisopropoxy group; examples of alkenyloxy groupsinclude C2-10 alkenyloxy groups and fluorine-containing alkenyloxygroups such as a vinyloxy group, a 1-propenyloxy group, a 2-propenyloxygroup, an isopropenyloxy group, a 2-butenyloxy group, a 3-butenyloxygroup and a 1,3-butadienyloxy group; examples of alkynyloxy groupsinclude C2-10 alkynyloxy groups and fluorine-containing alkynyloxygroups such as an ethynyloxy group, a 2-propynyloxy group, and a1,1-dimethyl-2-propynyloxy group; examples of cycloalkoxy groups includeC3-10 cycloalkoxy groups and fluorine-containing cycloalkoxy groups suchas a cyclopentyloxy group and a cyclohexyloxy group; examples ofcycloalkenyloxy groups include C3-10 cycloalkenyloxy groups andfluorine-containing cycloalkenyloxy groups such as a cyclo pentenyloxygroup and a cyclohexenyloxy group; and examples of aryloxy groupsinclude C6-10 aryloxy groups and fluorine-containing aryloxy groups suchas a phenyloxy group, a tolyloxy group and a xylyloxy group.

In the above general formulae (2) and (4), those represented by X,specifically: examples of alkyl groups include C1-10 alkyl groups andfluorine-containing alkyl groups such as a methyl group, an ethyl group,a propyl group, an isopropyl group, a butyl group, a secondary butylgroup, a tertiary butyl group, a pentyl group, a trifluoromethyl group,a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a2,2,3,3-tetrafluoropropyl group and a 1,1,1,3,3,3-hexafluoroisopropylgroup; examples of alkenyl groups include C2-10 alkenyl groups andfluorine-containing alkenyl groups such as a vinyl group, a 1-propenylgroup, a 2-propenyl group, an isopropenyl group, a 2-butenyl group, a3-butenyl group and a 1,3-butadienyl group; examples of alkynyl groupsinclude C2-10 alkynyl groups and fluorine-containing alkynyl groups suchas an ethynyl group, a 2-propynyl group and 1,1-dimethyl-2-propynylgroup; examples of cycloalkyl groups include C3-10 cycloalkyl groups andfluorine-containing cycloalkyl groups such as a cyclopentyl group and acyclohexyl group; examples of cycloalkenyl groups include C3-10cycloalkenyl groups and fluorine-containing cycloalkenyl groups such asa cyclopentenyl group and a cyclohexenyl group; and examples of arylgroups include C6-10 aryl groups and fluorine-containing aryl groupssuch as a phenyl group, a tolyl group and a xylyl group.

Examples of the divalent imide anions described in the above generalformulae (1) to (4) include, more specifically, the following compoundsNo. 1 to No. 18. However, the imide anions to be used in the presentinvention are not limited in any way by the following examples.

The salts having the imide anions, which are represented by any one ofthe above general formulae (1) to (4), can be produced by variousmethods. While production processes therefor are not limited, forexample, the salts can be obtained by reacting the correspondingphosphoramide (H₂NP(═O) R³O⁻) or sulfamic acid (H₂NSO₃ ⁻) with thecorresponding phosphonyl chloride (P(═O)R¹R²Cl) or sulfonyl chloride(XSO₂Cl) in the presence of an organic base or an inorganic base.

The kinds of the non-aqueous solvent to be used for the electrolyticsolution of the present invention are not particularly limited, and anykinds of the non-aqueous solvents can be used. The specific examplesthereof include cyclic carbonates such as propylene carbonate, ethylenecarbonate, and butylene carbonate, linear carbonates such as diethylcarbonate, dimethyl carbonate, and ethyl methyl carbonate, cyclic esterssuch as γ-butyrolactone and γ-valerolactone, linear esters such asmethyl acetate and methyl propionate, cyclic ethers such astetrahydrofuran, 2-methyltetrahydrofuran, and dioxane, linear etherssuch as dimethoxyethane and diethylether, and sulfone compounds orsulfoxide compounds such as dimethyl sulfoxide and sulfolane. Anotherexample thereof in a category differing from non-aqueous solvents is anionic liquid and the like. Furthermore, the non-aqueous solvents to beused in the present invention may be used singly or a combination of twoor more solvents mixed at any ratio depending on applications. Of theseexamples, in view of electrochemical stability against itsoxidation-reduction and chemical stability relating to heat or reactionwith the above solute, particularly propylene carbonate, ethylenecarbonate, diethyl carbonate, dimethyl carbonate, and ethyl methylcarbonate are preferred.

The kinds of the above solutes to be used for the electrolytic solutionfor a non-aqueous electrolyte battery of the present invention are notparticularly limited, and any electrolytic salts can be used. Thespecific examples thereof include: in the case of a lithium battery anda lithium ion battery, electrolytic salts represented by LiPF₆,LiPF₂(O₂O₄)₂, LiPF₄(C₂O₄), LiP(C₂O₄)₃, LiBF₂(C₂O₄), LiB(C₂O₄)₂, LiPO₂F₂,LiN(F₂PO)₂, LiN(FSO₂)₂, LiN(CF₃SO₂)₂, LiBF₄, LiClO₄, LiAsF₆, LiSbF₆,LiCF₃SO₃, LiN(C₂F₅SO₂)₂, LiN(CF₃SO₂)(C₄F₉SO₂), LiC(CF₃SO₂)₃,LiPF₃(C₃F₇)₃, LiB(CF₃)₄, and LiBF₃(C₂F₅); and in the case of a sodiumion battery, electrolytic salts represented by NaPF₆, NaPF₂(C₂O₄)₂,NaPF₄(C₂O₄), NaP(C₂O₄)₃, NaBF₂(C₂O₄), NaB(C₂O₄)₂, NaPO₂F₂, NaN(F₂PO)₂,NaN(FSO₂)₂, NaN(CF₃SO₂)₂, NaBF₄, NaClO₄, NaAsF₆, NaSbF₆, NaCF₃SO₃,NaN(C₂F₅SO₂)₂, NaN(CF₃SO₂)(C₄F₉SO₂), NaC(CF₃SO₂)₃, NaPF₃(C₃F₇)₃,NaB(CF₃)₄, and NaBF₃(O₂F₅). These solutes may be used singly or in acombination of two or more solutes mixed at any ratio depending onapplications. Of these examples, in view of energy density, outputcharacteristics, life, and the like for a battery, LiPF₆, LiPF₂(C₂O₄)₂,LiPF₄(C₂O₄), LiP(C₂O₄)₃, LiBF₂(C₂O₄), LiB(C₂O₄)₂, LiPO₂F₂, LiN(F₂PO)₂,LiN(FSO₂)₂, LiN(CF₃SO₂)₂, LiBF₄, NaPF₆, NaPF₂(C₂O₄)₂, NaPF₄(C₂O₄),NaP(C₂O₄)₃, NaBF₂(C₂O₄), NaB(C₂O₄)₂, NaPO₂F₂, NaN(F₂PO)₂, NaN(FSO₂)₂,NaN(CF₃SO₂)₂, and NaBF₄ are preferred.

A preferable combination of the solutes is, for example, a combinationof at least one solute selected from the group consisting ofLiPF₂(C₂O₄)₂, LiPF₄(C₂O₄), LiP(O₂O₄)₃, LiBF₂(C₂O₄), LiB(C₂O₄)₂, LiPO₂F₂,LiN(F₂PO)₂, LiN(FSO₂)₂, LiN(CF₃SO₂)₂, and LiBF₄, with LiPF₆.

The ratio (molar ratio when LiPF₆ is used as 1 mole) generally rangesfrom 1:0.001 to 1:0.5, and preferably ranges from 1:0.01 to 1:0.2, whenat least one solute selected from the group consisting of LiPF₂(C₂O₄)₂,LiPF₄(C₂O₄), LiP(C₂O₄)₃, LiBF₂(C₂O₄), LiB(C₂O₄)₂, LiPO₂F₂, LiN(F₂PO)₂,LiN(FSO₂)₂, LiN(CF₃SO₂)₂ and LiBF₄ is used in combination with LiPF₆ assolutes. The use of solutes in combination at the above ratio canprovide an effect of further improving various battery characteristics.On the other hand, if the proportion of LiPF₆ is lower than that in thecase of 1:0.5, the ionic conductance of the electrolytic solution islowered, and the resistance tends to increase.

While the concentration of these solutes is not particularly limited,the lower limit thereof is preferably 0.5 mol/L or more, more preferably0.7 mol/L or more, and further preferably 0.9 mol/L or more. Moreover,the upper limit thereof is preferably 2.5 mol/L or less, more preferably2.0 mol/L or less, and further preferably 1.5 mol/L or less. In thiscase, when plural kinds of the solutes are used, the concentration ofthe total amount of the solutes is preferably within the above range. Ifthe concentration is lower than 0.5 mol/L, ionic conductance is lowered,and the cycle characteristic and output characteristic of thenon-aqueous electrolyte battery tend to decrease. On the other hand, ifthe concentration exceeds 2.5 mol/L, the viscosity of the electrolyticsolution for a non-aqueous electrolyte battery is increased, and as aresult the ionic conductance tends to decrease. Accordingly, there is arisk of lowering the cycle characteristics and the outputcharacteristics of the non-aqueous electrolyte battery.

When a large amount of the solutes is dissolved at once in a non-aqueoussolvent, the liquid temperature may increase because of the heat of thedissolution of the solute(s). If the liquid temperature increasesremarkable, the decomposition of the fluorine-containing electrolyticsalt is accelerated and thus hydrogen fluoride may be generated.Hydrogen fluoride causes deterioration in battery performance and thusis not preferred. Therefore, while the liquid temperature at which thesolute(s) is dissolved in a non-aqueous solvent is not particularlylimited, −20° C. to 80° C. is preferably, and 0° C. to 60° C. is morepreferably.

The basic constitution of the electrolytic solution for a non-aqueouselectrolyte battery of the present invention is as described above. Anadditive that is generally used may be added at any ratio to theelectrolytic solution for a non-aqueous electrolyte battery of thepresent invention, as long as the gist of the present invention is notimpaired. Specific examples thereof include compounds having an effectof preventing overcharge, an effect of forming a negative electrodefilm, and an effect of protecting a positive electrode, such ascyclohexylbenzene, biphenyl, t-butylbenzene, vinylene carbonate, vinylethylene carbonate, difluoroanisole, fluoroethylene carbonate, propanesultone, succinonitrile, and dimethyl vinylene carbonate. Moreover, asused in a non-aqueous electrolyte battery referred to as a lithiumpolymer battery, an electrolytic solution for a non-aqueous electrolytebattery can be pseudo-solidified with a gelling agent or a cross-linkedpolymer and then used.

Next, the constitution of the non-aqueous electrolyte battery of thepresent invention will be explained. The non-aqueous electrolyte batteryof the present invention is characterized by the use of the aboveelectrolytic solution for a non-aqueous electrolyte battery of thepresent invention. Members that are generally used for a non-aqueouselectrolyte battery are used as other constitutional members.Specifically, such a battery is composed of, for example, a positiveelectrode, a negative electrode capable of occluding and releasingcations, a collector, a separator, and a container.

Examples of an negative electrode material to be used herein are notparticularly limited. However, in the case of a lithium battery and alithium ion battery, they include a lithium metal, an alloy of a lithiummetal and another metal, or intermetallic compounds, various carbonmaterials (e.g., artificial graphite and natural graphite), a metaloxide, a metal nitride, tin (elemental substance), a tin compound,silicon (elemental substance), a silicon compound, an activated carbon,and a conductive polymer.

Examples of carbon materials include easily graphitizable carbon, hardlygraphitizable carbon (hard carbon) having the interplanar spacing of(002) plane of 0.37 nm or more, and graphite having the interplanarspacing of (002) plane of 0.34 nm or less. More specific examplesthereof include pyrolytic carbon, cokes, glassy carbon fibers, organicpolymer compound fired bodies, activated carbon or carbon blacks. Ofthese, cokes include a pitch coke, a needle coke or a petroleum coke. Anorganic polymer compound fired body is referred to as a product producedby burning a phenol resin, a furan resin or the like at an appropriatetemperature, to carbonize it. Carbon materials are preferred since thecrystal structure changes much less due to the occlusion and release oflithium, so that a high energy density and an excellent cyclecharacteristic can be obtained. In addition, the shape of a carbonmaterial may be fibrous, spherical, granular or squamous. Furthermore,amorphous carbon or a graphite material whose surface is coated withamorphous carbon is more preferred since the reactivity between thematerial surface and the electrolytic solution decreases.

Examples of a positive electrode material to be used herein include, butare not particularly limited to, in the case of a lithium battery and alithium ion battery, lithium-containing transition metal compositeoxides such as LiCoO₂, LiNiO₂, LiMnO₂, and LiMn₂O₄, a mixture of aplurality of such lithium-containing transition metal composite oxideswherein plural kinds of transition metals, e.g., Co, Mn, and Ni, arecontained, those wherein the transition metals of the lithium-containingtransition metal composite oxides thereof are partially substituted withother transition metals, phosphate compounds of transition metalsreferred to as olivine such as LiFePO₄, LiCoPO₄ and LiMnPO₄, oxides suchas TiO₂, V₂O₅ and MoO₃, sulfides such as TiS₂ and FeS, or conductivepolymers such as polyacetylene, polyparaphenylene, polyaniline andpolypyrrole, activated carbon, polymers that generate radicals, andcarbon materials.

To a positive electrode or negative electrode material, acetylene black,Ketjen black, carbon fiber, or graphite as a conductive material andpolytetrafluoroethylene, polyvinylidene fluoride, SBR resin or the likeas a binder material are added, and then the resultant material isformed into a sheet, so that an electrode sheet can be produced.

As a separator for preventing the contact between a positive electrodeand a negative electrode, a nonwoven fabric or porous sheet made ofpolypropylene, polyethylene, paper, and glass fiber is used.

A non-aqueous electrolyte battery in a coin shape, cylindrical shape,square shape, laminated aluminum sheet form, or the like is assembledwith the above elements.

EXAMPLES

The present invention will be more specifically explained with referenceto Examples, but the scope of the present invention is not limited bythese Examples.

Example 1-1

A mixed solvent containing ethylene carbonate, propylene carbonate,dimethyl carbonate and ethyl methyl carbonate at a volume ratio of2:1:3:4 was used as a non-aqueous solvent. LiPF₆ as a solute wasdissolved in the solvent to a concentration of 1.0 mol/L, and the abovecompound No. 1 of dilithium salt was dissolved as a salt having adivalent imide anion to a concentration of 1.0 mass %. As shown in Table1, electrolytic solutions for non-aqueous electrolyte batteries wereprepared. In addition, the above preparation was performed whilemaintaining the liquid temperature at 25° C.

Cells were prepared using the electrolytic solution,LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂ as a positive electrode material, andgraphite as a negative electrode material. The cells were actuallyevaluated for a cycle characteristic and a low-temperature outputcharacteristic of the batteries. A cell for a test was prepared asfollows.

LiNi_(1/3)Mn_(1/3)CO_(1/3)O₂ powder (90 mass %) was mixed with 5 mass %of polyvinylidene fluoride (PVDF) as a binder and 5 mass % of acetyleneblack as a conductive material. N-methylpyrrolidone was further added tothe mixture and then prepared into a paste. The paste was applied ontoan aluminum foil, and dried, thereby preparing a positive electrode fora test. Graphite powder (90 mass %) was mixed with 10 mass % of PVDF asa binder and then N-methylpyrrolidone was further added to form aslurry. The slurry was applied onto a copper foil and dried at 150° C.for 12 hours, thereby obtaining a negative electrode for the test. Apolyethylene separator was impregnated with the prepared electrolyticsolution, so as to assemble a 50 mAh cell armored with an aluminumlaminate.

A charge and discharge test was conducted using the cells prepared bythe above methods in order to evaluate a high-temperature cyclecharacteristic and a low-temperature output characteristic. Theevaluation results are shown in Table 4.

High-Temperature Cycle Characteristics Test

The charge and discharge were conducted at an ambient temperature of 45°C. to evaluate the cycle characteristic. The charging was performed to4.3 V, and discharging was performed to 3.0 V, and then a charge anddischarge cycle was repeated at current density of 5.7 mA/cm². The cellswere evaluated for the degree of the deterioration based on dischargecapacity maintenance % after 200 cycles (evaluation of cyclecharacteristics). Discharge capacity maintenance % was determined by thefollowing formula.

Discharge capacity maintenance (%)=(discharge capacity after 200cycles/initial discharge capacity)×100  <Discharge capacity maintenance% after 200 cycles>

Low-Temperature Output Characteristic Test

Under an ambient temperature of 25° C., a constant current and constantvoltage method was conducted with an upper limit charging voltage of 4.3V, wherein charging and discharging were performed with a currentdensity of 0.38 mA/cm². The discharge capacity at this time wasdesignated as discharge capacity A. Subsequently, under an ambienttemperature of −30° C., a constant current and constant voltage methodwas conducted with an upper limit charging voltage of 4.3 V, whereincharging was performed with a current density of 0.38 mA/cm², and thendischarging was performed with a constant current density of 9.5 mA/cm²to discharge end voltage of 3.0 V. The discharge capacity at this timewas designated as discharge capacity B, a value determined by“(discharge capacity B/discharge capacity A)×100” was designated as highoutput capacity maintenance (%), and was used for evaluating thelow-temperature output characteristic of the cells.

Examples 1-2 to 1-155, and Comparative Examples 1-1 to 1-17

As shown in Tables 1 to 3, the electrolytic solutions for non-aqueouselectrolyte batteries were prepared and cells were produced in a mannersimilar to Example 1-1, except that the kinds and concentrations (mol/L)of solutes and the kinds and concentrations (mass %) of the salts havingimide anions were varied, and then the batteries were evaluated. Theevaluation results are shown in Tables 4 to 6. In this case, theevaluation results of Examples 1-1 to 1-155 and Comparative examples 1-1to 1-17 are indicated as relative values when the value of Comparativeexample 1-1 is designated as 100.

In addition, the following compounds Nos. 19 to 24 were used as thesalts having imide anions used in Comparative examples 1-2 to 1-7.

TABLE 1 Solute 1 Solute 2 Salt having imide anion ConcentrationConcentration Compound Counter Concentration Kind [mol/L] Kind [mol/L]No. cation [mass %] Electrolytic LiPF₆ 1.0 None 0 No. 1 2Li⁺ 1.0solution No. 1 Electrolytic 0.005 solution No. 2 Electrolytic 0.05solution No. 3 Electrolytic 0.1 solution No. 4 Electrolytic 0.5 solutionNo. 5 Electrolytic 2.0 solution No. 6 Electrolytic 10.0 solution No. 7Electrolytic No. 2 1.0 solution No. 8 Electrolytic No. 3 1.0 solutionNo. 9 Electrolytic No. 4 1.0 solution No. 10 Electrolytic No. 5 1.0solution No. 11 Electrolytic No. 6 1.0 solution No. 12 Electrolytic No.7 1.0 solution No. 13 Electrolytic No. 8 1.0 solution No. 14Electrolytic No. 9 1.0 solution No. 15 Electrolytic No. 10 1.0 solutionNo. 16 Electrolytic No. 11 1.0 solution No. 17 Electrolytic No. 12 1.0solution No. 18 Electrolytic No. 13 1.0 solution No. 19 Electrolytic No.14 1.0 solution No. 20 Electrolytic No. 15 1.0 solution No. 21Electrolytic No. 16 1.0 solution No. 22 Electrolytic No. 17 1.0 solutionNo. 23 Electrolytic No. 18 1.0 solution No. 24 Electrolytic No. 1 Li⁺,H⁺ 1.0 solution No. 25 Electrolytic No. 6 1.0 solution No. 26Electrolytic No. 7 1.0 solution No. 27 Electrolytic No. 10 1.0 solutionNo. 28 Electrolytic No. 11 1.0 solution No. 29 Electrolytic No. 15 1.0solution No. 30 Electrolytic No. 16 1.0 solution No. 31 Electrolytic No.1 Li⁺, Na⁺ 1.0 solution No. 32 Electrolytic No. 6 1.0 solution No. 33Electrolytic No. 7 1.0 solution No. 34 Electrolytic No. 10 1.0 solutionNo. 35 Electrolytic No. 11 1.0 solution No. 36 Electrolytic No. 15 1.0solution No. 37 Electrolytic No. 16 1.0 solution No. 38 Electrolytic No.1 Li⁺, K⁺ 1.0 solution No. 39 Electrolytic No. 6 1.0 solution No. 40Electrolytic No. 7 1.0 solution No. 41 Electrolytic No. 10 1.0 solutionNo. 42 Electrolytic No. 11 1.0 solution No. 43 Electrolytic No. 15 1.0solution No. 44 Electrolytic No. 16 1.0 solution No. 45 Electrolytic No.1 Li⁺, (C₂H₅)₄N⁺ 1.0 solution No. 46 Electrolytic No. 6 1.0 solution No.47 Electrolytic No. 7 1.0 solution No. 48 Electrolytic No. 10 1.0solution No. 49 Electrolytic No. 11 1.0 solution No. 50 Electrolytic No.15 1.0 solution No. 51 Electrolytic No. 16 1.0 solution No. 52Electrolytic No. 1 Li⁺, (C₂H₅)₄P⁺ 1.0 solution No. 53 Electrolytic No. 61.0 solution No. 54 Electrolytic No. 7 1.0 solution No. 55 ElectrolyticNo. 10 1.0 solution No. 56 Electrolytic No. 11 1.0 solution No. 57Electrolytic No. 15 1.0 solution No. 58 Electrolytic No. 16 1.0 solutionNo. 59

TABLE 2 Solute 1 Solute 2 Salt having imide anion ConcentrationConcentration Compound Counter Concentration Kind [mol/L] Kind [mol/L]No. cation [mass %] Electrolytic LiPF₆ 1.0 None 0 No. 1 2Na⁺ 1.0solution No. 60 Electrolytic No. 6 1.0 solution No. 61 Electrolytic No.7 1.0 solution No. 62 Electrolytic No. 10 1.0 solution No. 63Electrolytic No. 11 1.0 solution No. 64 Electrolytic No. 15 1.0 solutionNo. 65 Electrolytic No. 16 1.0 solution No. 66 Electrolytic No. 12(C₂H₅)₄N⁺ 1.0 solution No. 67 Electrolytic No. 6 1.0 solution No. 68Electrolytic No. 7 1.0 solution No. 69 Electrolytic No. 10 1.0 solutionNo. 70 Electrolytic No. 11 1.0 solution No. 71 Electrolytic No. 15 1.0solution No. 72 Electrolytic No. 16 1.0 solution No. 73 Electrolytic No.1 2(C₂H₅)₄P⁺ 1.0 solution No. 74 Electrolytic No. 6 1.0 solution No. 75Electrolytic No. 7 1.0 solution No. 76 Electrolytic No. 10 1.0 solutionNo. 77 Electrolytic No. 11 1.0 solution No. 78 Electrolytic No. 15 1.0solution No. 79 Electrolytic No. 16 1.0 solution No. 80 ElectrolyticLiPF₂(C₂O₄)₂ 0.001 No. 1 2Li⁺ 1.0 solution No. 81 Electrolytic 0.01 1.0solution No. 82 Electrolytic 0.05 1.0 solution No. 83 Electrolytic 0.11.0 solution No. 84 Electrolytic 0.2 1.0 solution No. 85 Electrolytic0.5 1.0 solution No. 86 Electrolytic 0.1 No. 6 1.0 solution No. 87Electrolytic 0.1 No. 7 1.0 solution No. 88 Electrolytic 0.1 No. 10 1.0solution No. 89 Electrolytic 0.1 No. 11 1.0 solution No. 90 Electrolytic0.1 No. 15 1.0 solution No. 91 Electrolytic 0.1 No. 16 1.0 solution No.92 Electrolytic LiPF₄(C₂O₄) 0.1 No. 1 1.0 solution No. 93 Electrolytic0.1 No. 6 1.0 solution No. 94 Electrolytic 0.1 No. 7 1.0 solution No. 95Electrolytic 0.1 No. 10 1.0 solution No. 96 Electrolytic 0.1 No. 11 1.0solution No. 97 Electrolytic 0.1 No. 15 1.0 solution No. 98 Electrolytic0.1 No. 16 1.0 solution No. 99 Electrolytic LiP(C₂O₄)₃ 0.1 No. 1 1.0solution No. 100 Electrolytic 0.1 No. 6 1.0 solution No. 101Electrolytic 0.1 No. 7 1.0 solution No. 102 Electrolytic 0.1 No. 10 1.0solution No. 103 Electrolytic 0.1 No. 11 1.0 solution No. 104Electrolytic 0.1 No. 15 1.0 solution No. 105 Electrolytic 0.1 No. 16 1.0solution No. 106 Electrolytic LiBF₂(C₂O₄) 0.1 No. 1 1.0 solution No. 107Electrolytic 0.1 No. 6 1.0 solution No. 108 Electrolytic 0.1 No. 7 1.0solution No. 109 Electrolytic 0.1 No. 10 1.0 solution No. 110Electrolytic 0.1 No. 11 1.0 solution No. 111 Electrolytic 0.1 No. 15 1.0solution No. 112 Electrolytic 0.1 No. 16 1.0 solution No. 113Electrolytic LiB(C₂O₄)₂ 0.1 No. 1 1.0 solution No. 114 Electrolytic 0.1No. 6 1.0 solution No. 115 Electrolytic 0.1 No. 7 1.0 solution No. 116Electrolytic 0.1 No. 10 1.0 solution No. 117 Electrolytic 0.1 No. 11 1.0solution No. 118 Electrolytic 0.1 No. 15 1.0 solution No. 119Electrolytic 0.1 No. 16 1.0 solution No. 120

TABLE 3 Solute 1 Solute 2 Salt having imide anion ConcentrationConcentration Compound Counter Concentration Kind [mol/L] Kind [mol/L]No. cation [mass %] Electrolytic LiPF₆ 1.0 LiPO₂F₂ 0.1 No. 1 2Li⁺ 1.0solution No. 121 Electrolytic 0.1 No. 6 1.0 solution No. 122Electrolytic 0.1 No. 7 1.0 solution No. 123 Electrolytic 0.1 No. 10 1.0solution No. 124 Electrolytic 0.1 No. 11 1.0 solution No. 125Electrolytic 0.1 No. 15 1.0 solution No. 126 Electrolytic 0.1 No. 16 1.0solution No. 127 Electrolytic LiN(F₂PO)₂ 0.1 No. 1 1.0 solution No. 128Electrolytic 0.1 No. 6 1.0 solution No. 129 Electrolytic 0.1 No. 7 1.0solution No. 130 Electrolytic 0.1 No. 10 1.0 solution No. 131Electrolytic 0.1 No. 11 1.0 solution No. 132 Electrolytic 0.1 No. 15 1.0solution No. 133 Electrolytic 0.1 No. 16 1.0 solution No. 134Electrolytic LiN(FSO₂)₂ 0.1 No. 1 1.0 solution No. 135 Electrolytic 0.1No. 6 1.0 solution No. 136 Electrolytic 0.1 No. 7 1.0 solution No. 137Electrolytic 0.1 No. 10 1.0 solution No. 138 Electrolytic 0.1 No. 11 1.0solution No. 139 Electrolytic 0.1 No. 15 1.0 solution No. 140Electrolytic 0.1 No. 16 1.0 solution No. 141 Electrolytic LiN(CF₃SO₂)₂0.1 No. 1 1.0 solution No. 142 Electrolytic 0.1 No. 6 1.0 solution No.143 Electrolytic 0.1 No. 7 1.0 solution No. 144 Electrolytic 0.1 No. 101.0 solution No. 145 Electrolytic 0.1 No. 11 1.0 solution No. 146Electrolytic 0.1 No. 15 1.0 solution No. 147 Electrolytic 0.1 No. 16 1.0solution No. 148 Electrolytic LiBF₄ 0.1 No. 1 1.0 solution No. 149Electrolytic 0.1 No. 6 1.0 solution No. 150 Electrolytic 0.1 No. 7 1.0solution No. 151 Electrolytic 0.1 No. 10 1.0 solution No. 152Electrolytic 0.1 No. 11 1.0 solution No. 153 Electrolytic 0.1 No. 15 1.0solution No. 154 Electrolytic 0.1 No. 16 1.0 solution No. 155Electrolytic None 0 None — 0 solution No. 156 Electrolytic No. 19 Li⁺1.0 solution No. 157 Electrolytic No. 20 1.0 solution No. 158Electrolytic No. 21 1.0 solution No. 159 Electrolytic No. 22 1.0solution No. 160 Electrolytic No. 23 1.0 solution No. 161 ElectrolyticNo. 24 1.0 solution No. 162 Electrolytic LiPF₂(C₂O₄₎2 0.1 None — 0solution No. 163 Electrolytic LiPF₄(C₂O₄) 0.1 0 solution No. 164Electrolytic LiP(C₂O₄)₃ 0.1 0 solution No. 165 Electrolytic LiBF₂(C₂O₄)0.1 0 solution No. 166 Electrolytic LiB(C₂O₄)₂ 0.1 0 solution No. 167Electrolytic LiPO₂F₂ 0.1 0 solution No. 168 Electrolytic LiN(F₂PO)₂ 0.10 solution No. 169 Electrolytic LiN(FSO₂)₂ 0.1 0 solution No. 170Electrolytic LiN(CF₃SO₂)₂ 0.1 0 solution No. 171 Electrolytic LiBF₄ 0.10 solution No. 172

TABLE 4 Discharge capacity Negative maintenance High power ElectrolyticPositive electrode after 200 capacity solution electrode Active cycles*maintenance* No. Active material material [%] [%] Example No. 1LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂ Graphite 120 127 1-1 Example No. 2 103 1041-2 Example No. 3 110 110 1-3 Example No. 4 114 115 1-4 Example No. 5117 122 1-5 Example No. 6 113 115 1-6 Example No. 7 107 105 1-7 ExampleNo. 8 116 118 1-8 Example No. 9 117 117 1-9 Example No. 10 118 115 1-10Example No. 11 115 117 1-11 Example No. 12 118 125 1-12 Example No. 13113 111 1-13 Example No. 14 114 113 1-14 Example No. 15 118 114 1-15Example No. 16 117 116 1-16 Example No. 17 115 123 1-17 Example No. 18108 108 1-18 Example No. 19 109 107 1-19 Example No. 20 112 107 1-20Example No. 21 117 124 1-21 Example No. 22 118 120 1-22 Example No. 23116 122 1-23 Example No. 24 115 121 1-24 Example No. 25 119 126 1-25Example No. 26 118 124 1-26 Example No. 27 112 111 1-27 Example No. 28116 115 1-28 Example No. 29 115 122 1-29 Example No. 30 117 122 1-30Example No. 31 117 120 1-31 Example No. 32 119 125 1-32 Example No. 33117 123 1-33 Example No. 34 111 110 1-34 Example No. 35 116 114 1-35Example No. 36 113 121 1-36 Example No. 37 115 123 1-37 Example No. 38117 118 1-38 Example No. 39 115 120 1-39 Example No. 40 113 118 1-40Example No. 41 108 107 1-41 Example No. 42 113 109 1-42 Example No. 43111 116 1-43 Example No. 44 112 118 1-44 Example No. 45 113 114 1-45Example No. 46 114 121 1-46 Example No. 47 113 120 1-47 Example No. 48108 108 1-48 Example No. 49 112 113 1-49 Example No. 50 110 115 1-50Example No. 51 113 115 1-51 Example No. 52 113 114 1-52 Example No. 53119 124 1-53 Example No. 54 116 123 1-54 Example No. 55 111 110 1-55Example No. 56 115 114 1-56 Example No. 57 114 121 1-57 Example No. 58115 121 1-58 Example No. 59 115 119 1-59 *Relative value when the valueof Comparative example 1-1 is designated as 100.

TABLE 5 Discharge capacity Negative maintenance High power ElectrolyticPositive electrode after 200 capacity solution electrode Active cycles*maintenance* No. Active material material [%] [%] Example No. 60LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂ Graphite 117 123 1-60 Example No. 61 115121 1-61 Example No. 62 110 109 1-62 Example No. 63 115 113 1-63 ExampleNo. 64 112 120 1-64 Example No. 65 114 117 1-65 Example No. 66 115 1151-66 Example No. 67 111 116 1-67 Example No. 68 109 114 1-68 Example No.69 107 107 1-69 Example No. 70 109 109 1-70 Example No. 71 109 115 1-71Example No. 72 110 115 1-72 Example No. 73 111 113 1-73 Example No. 74110 114 1-74 Example No. 75 108 112 1-75 Example No. 76 107 106 1-76Example No. 77 109 107 1-77 Example No. 78 108 112 1-78 Example No. 79109 113 1-79 Example No. 80 110 111 1-80 Example No. 81 121 128 1-81Example No. 82 125 130 1-82 Example No. 83 129 133 1-83 Example No. 84133 136 1-84 Example No. 85 134 136 1-85 Example No. 86 130 132 1-86Example No. 87 130 132 1-87 Example No. 88 124 115 1-88 Example No. 89128 122 1-89 Example No. 90 126 130 1-90 Example No. 91 128 137 1-91Example No. 92 129 131 1-92 Example No. 93 129 132 1-93 Example No. 94128 130 1-94 Example No. 95 122 115 1-95 Example No. 96 127 120 1-96Example No. 97 125 128 1-97 Example No. 98 126 129 1-98 Example No. 99128 125 1-99 Example No. 100 132 130 1-100 Example No. 101 130 127 1-101Example No. 102 125 113 1-102 Example No. 103 128 118 1-103 Example No.104 127 125 1-104 Example No. 105 129 126 1-105 Example No. 106 129 1231-106 Example No. 107 128 133 1-107 Example No. 108 127 130 1-108Example No. 109 121 117 1-109 Example No. 110 125 122 1-110 Example No.111 124 128 1-111 Example No. 112 126 130 1-112 Example No. 113 127 1261-113 Example No. 114 127 128 1-114 Example No. 115 125 125 1-115Example No. 116 120 111 1-116 Example No. 117 126 116 1-117 Example No.118 123 124 1-118 Example No. 119 124 124 1-119 Example No. 120 125 1211-120 *Relative value when the value of Comparative example 1-1 isdesignated as 100.

TABLE 6 Discharge capacity Positive Negative maintenance High powerElectrolytic electrode electrode after 200 capacity solution ActiveActive cycles* maintenance* No. material material [%] [%] Example No.121 LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂ Graphite 125 132 1-121 Example No. 122123 130 1-122 Example No. 123 117 116 1-123 Example No. 124 122 1201-124 Example No. 125 120 128 1-125 Example No. 126 121 128 1-126Example No. 127 122 125 1-127 Example No. 128 121 130 1-128 Example No.129 120 128 1-129 Example No. 130 115 113 1-130 Example No. 131 119 1191-131 Example No. 132 117 125 1-132 Example No. 133 119 127 1-133Example No. 134 120 123 1-134 Example No. 135 122 128 1-135 Example No.136 120 126 1-136 Example No. 137 115 112 1-137 Example No. 138 118 1181-138 Example No. 139 117 125 1-139 Example No. 140 119 125 1-140Example No. 141 120 121 1-141 Example No. 142 121 127 1-142 Example No.143 119 125 1-143 Example No. 144 114 111 1-144 Example No. 145 119 1171-145 Example No. 146 116 123 1-146 Example No. 147 118 124 1-147Example No. 148 119 120 1-148 Example No. 149 120 127 1-149 Example No.150 119 125 1-150 Example No. 151 113 111 1-151 Example No. 152 117 1171-152 Example No. 153 115 123 1-153 Example No. 154 117 124 1-154Example No. 155 119 120 1-155 Comparative No. 156 100 100 example 1-1Comparative No. 157 104 104 example 1-2 Comparative No. 158 103 104example 1-3 Comparative No. 159 103 103 example 1-4 Comparative No. 160102 103 example 1-5 Comparative No. 161 102 101 example 1-6 ComparativeNo. 162 110 100 example 1-7 Comparative No. 163 112 108 example 1-8Comparative No. 164 110 105 example 1-9 Comparative No. 165 112 102example 1-10 Comparative No. 166 109 106 example 1-11 Comparative No.167 107 101 example 1-12 Comparative No. 168 105 105 example 1-13Comparative No. 169 102 103 example 1-14 Comparative No. 170 102 101example 1-15 Comparative No. 171 101 100 example 1-16 Comparative No.172 100 100 example 1-17 *Relative value when the value of Comparativeexample 1-1 is designated as 100.

As a result of comparison of the above results, it was confirmed thatboth a high-temperature cycle characteristic and a low-temperatureoutput characteristic were improved in Examples 1-1 to 1-24 in which thesalts having divalent imide anions were added, as compared withComparative example 1-1 in which no such salt was added. Similarly, itwas confirmed that a high-temperature cycle characteristic and alow-temperature output characteristic were improved in Examples 1-1 and1-8 to 1-24 in which the salts having divalent imide anions of thepresent invention were contained at the same concentration (1.0 mass %),as compared with Comparative examples 1-2 to 1-7 in which salts havingmonovalent imide anions were used.

Further, for example, among Examples 1-1 and 1-8 to 1-24 in which thecompositional ratios of the electrolytic solutions were the same, it wasconfirmed that the Examples (Examples 1-1, 1-8 to 1-17 and 1-21 to 1-24)in which the salts having imide anions having P—F bonds or S—F bondsprovided a low-temperature output characteristic which is better thanthat in the Examples (Examples 1-18 to 1-20) in which the salts havingimide anions with no P—F bond and no S—F bond were used. Furthermore, itwas confirmed that the higher the number of P—F bonds or S—F bonds inthe above salts having imide anions, the more the low-temperaturecharacteristic was improved.

Further, for example, among Examples 1-1 and 1-8 to 1-11 in which thesalt having the divalent imide anion represented by the general formula(1) was used, a better high-temperature cycle characteristic wasprovided in Examples 1-1 and 1-8 to 1-10 in which R¹ to R³ were afluorine atom or an organic group selected from the group consisting ofan alkenyloxy group and an alkynyloxy group, than that in Example 1-11in which R¹ to R³ are not the above groups.

Further, for example, among Examples 1-12 to 1-16 in which the salthaving the divalent imide anion represented by the general formula (2)was used, a better high-temperature cycle characteristic was provided inExamples 1-12 and 1-14 to 1-16 in which X was a fluorine atom or anorganic group selected from the group consisting of an alkoxy group, analkenyloxy group, and an alkynyloxy group, than that in Example 1-13 inwhich X is not the above group.

Further, for example, among Examples 1-21 to 1-24 in which the salthaving the divalent imide anion represented by the general formula (3)was used, it was confirmed that a better high-temperature cyclecharacteristic was provided in Examples 1-21 and 22 wherein R¹ and R²were a fluorine atom or an alkynyloxy group, than that in Examples 1-23and 24 wherein R¹ and R² are not such groups.

Further, for example, among Examples 1-17 to 1-20 in which the salthaving the divalent imide anion represented by the general formula (4)was used, it was confirmed that a better high-temperature cyclecharacteristic was provided in Examples 1-17, 1-19 and 1-20 in which Xwas a fluorine atom or an organic group selected from the groupconsisting of an alkoxy group and an alkynyloxy group, than that inExample 1-18 in which X is not such group.

It was confirmed in Examples 1-25 to 1-80 that the similar effects werealso obtained, specifically, in systems where the counter cations of thedivalent imide anions were varied.

Furthermore, even when LiPF₆ was mixed with another solute, it wasconfirmed that a high-temperature cycle characteristic and alow-temperature output characteristic were improved in Examples 1-81 to1-155 in which the salts having divalent imide anions were added, ascompared with Comparative examples 1-8 to 1-17 in which no salt having adivalent imide anion was added, and the similar effects were obtained.

Examples 2-1 to 2-21 and Comparative Examples 2-1 to 2-12

As shown in Table 7, the electrolytic solutions for non-aqueouselectrolyte batteries were prepared, cells were produced, and then thebatteries were evaluated in a manner similar to Example 1-1 except thatthe kinds of the negative electrodes and of the electrolytic solutionswere varied.

In this case, a negative electrode using Li₄Ti₅O₁₂ as the activematerial was prepared by mixing 90 mass % of Li₄Ti₅O₁₂ powder with 5mass % of PVDF as a binder and 5 mass % of acetylene black as aconductive agent, further adding N-methylpyrrolidone thereto, applyingthe thus obtained paste onto a copper foil, and then drying theresultant. When the resultant batteries were evaluated, theend-of-charge voltage was 2.8 V and the end-of-discharge voltage was 1.5V.

Furthermore, a negative electrode using graphite (containing silicon) asthe active material was prepared by mixing 81 mass % of graphite powderand 9 mass % of silicon powder with 5 mass % of PVDF as a binder and 5mass % of acetylene black as a conductive material, further addingN-methylpyrrolidone thereto, applying the thus obtained paste onto acopper foil, and then drying the resultant. When the resultant batterieswere evaluated, the end-of-charge voltage and the end-of-dischargevoltage were the same as those in Example 1-1.

Moreover, a negative electrode using hard carbon as the active materialwas prepared by mixing 90 mass % of hard carbon powder with 5 mass % ofPVDF as a binder and 5 mass % of acetylene black as a conductive agent,further adding N-methylpyrrolidone thereto, applying the thus obtainedpaste onto a copper foil, and then drying the resultant material. Whenthe resultant batteries were evaluated, the end-of-charge voltage was4.2 V and the end-of-discharge voltage was 2.2 V.

The evaluation results are shown in Table 7. In this case, theevaluation results of Examples 2-1 to 2-7 and Comparative examples 2-1to 2-4 are indicated as relative values when the value of Comparativeexample 2-1 is designated as 100. Moreover, the evaluation results ofExamples 2-8 to 2-14 and Comparative examples 2-5 to 2-8 are indicatedas relative values when the value of Comparative example 2-5 isdesignated as 100. Moreover, the evaluation results of Examples 2-15 to2-21 and Comparative examples 2-9 to 2-12 are indicated as relativevalues when the value of Comparative example 2-9 is designated as 100.

TABLE 7 Discharge capacity Positive Negative maintenance High powerElectrolytic electrode electrode after capacity solution Active Active200 cycles* maintenance* No. material material [%] [%] Example No. 1LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂ Li₄Ti₅O₁₂ 110 114 2-1 Example No. 12 109112 2-2 Example No. 13 106 105 2-3 Example No. 16 108 108 2-4 ExampleNo. 17 107 112 2-5 Example No. 21 108 112 2-6 Example No. 22 109 110 2-7Comparative No. 156 100 100 example 2-1 Comparative No. 157 101 101example 2-2 Comparative No. 161 101 100 example 2-3 Comparative No. 162100 100 example 2-4 Example No. 1 Graphite 117 122 2-8 (containingExample No. 12 silicon) 115 120 2-9 Example No. 13 110 107 2-10 ExampleNo. 16 115 112 2-11 Example No. 17 113 120 2-12 Example No. 21 114 1202-13 Example No. 22 115 116 2-14 Comparative No. 156 100 100 example 2-5Comparative No. 157 101 101 example 2-6 Comparative No. 161 101 101example 2-7 Comparative No. 162 100 100 example 2-8 Example No. 1 Hardcarbon 112 118 2-15 Example No. 12 111 116 2-16 Example No. 13 107 1082-17 Example No. 16 110 113 2-18 Example No. 17 110 116 2-19 Example No.21 111 116 2-20 Example No. 22 111 114 2-21 Comparative No. 156 100 100example 2-9 Comparative No. 157 102 101 example 2-10 Comparative No. 161101 101 example 2-11 Comparative No. 162 101 100 example 2-12 *Relativevalue in each corresponding battery constitution, when the value ofComparative example in which Electrolytic solution No. 156 was used isdesignated as 100.

Examples 3-1 to 3-28, and Comparative Examples 3-1 to 3-16

As shown in Table 8, the electrolytic solutions for non-aqueouselectrolyte batteries were prepared, the cells were produced, and thebatteries were evaluated in a manner similar to Example 1-1 except thatthe kinds of the positive electrodes, negative electrodes andelectrolytic solutions were varied.

In this case, the positive electrode using LiCoO₂ as the active materialwas prepared by mixing 90 mass % of LiCoO₂ powder with 5 mass % of PVDFas a binder and 5 mass % of acetylene black as a conductive material,further adding N-methylpyrrolidone thereto, applying the thus obtainedpaste onto an aluminum foil, and then drying the resultant material.

In Examples 3-1 to 3-7 and Comparative examples 3-1 to 3-4, in which theactive material of the negative electrode was graphite similarly toExample 1-1, when the resultant batteries were evaluated, theend-of-charge voltage was 4.2 V and the end-of-discharge voltage was 3.0V.

In Examples 3-8 to 3-14 and Comparative examples 3-5 to 3-8, in whichthe active material of the negative electrode was Li₄Ti₅O₁₂ similarly toExample 2-1, when the resultant batteries were evaluated, theend-of-charge voltage was 2.7 V and the end-of-discharge voltage was 1.5V.

In Examples 3-15 to 3-21 and Comparative examples 3-9 to 3-12, in whichthe active material of the negative electrode was graphite (containingsilicon) similarly to Example 2-8, when the resultant batteries wereevaluated, the end-of-charge voltage was 4.2V and the end-of-dischargevoltage was 3.0 V.

In Examples 3-22 to 3-28 and Comparative examples 3-13 to 3-16, in whichthe active material of the negative electrode was hard carbon similarlyto Example 2-15, when the resultant batteries were evaluated, theend-of-charge voltage was 4.1V and the end-of-discharge voltage was 2.2V.

Evaluation results are shown in Table 8. In this case, the evaluationresults of Examples 3-1 to 3-7 and Comparative examples 3-1 to 3-4 areindicated as relative values when the value of Comparative example 3-1is designated as 100. Furthermore, the evaluation results of Examples3-8 to 3-14 and Comparative examples 3-5 to 3-8 are indicated asrelative values when the value of Comparative example 3-5 is designatedas 100. Furthermore, the evaluation results of Examples 3-15 to 3-21 andComparative examples 3-9 to 3-12 are indicated as relative values whenthe value of Comparative example 3-9 is designated as 100. Furthermore,the evaluation results of Examples 3-22 to 3-28 and Comparative examples3-13 to 3-16 are indicated as relative values when the value ofComparative example 3-13 is designated as 100.

TABLE 8 Discharge capacity Positive Negative maintenance High powerElectrolytic electrode electrode after capacity solution Active Active200 cycles* maintenance* No. material material [%] [%] Example No. 1LiCoO₂ Graphite 119 125 3-1 Example No. 12 117 123 3-2 Example No. 13113 110 3-3 Example No. 16 116 115 3-4 Example No. 17 115 121 3-5Example No. 21 117 123 3-6 Example No. 22 117 119 3-7 Comparative No.156 100 100 example 3-1 Comparative No. 157 102 103 example 3-2Comparative No. 161 102 102 example 3-3 Comparative No. 162 100 100example 3-4 Example No. 1 Li₄Ti₅O₁₂ 110 113 3-8 Example No. 12 108 1113-9 Example No. 13 106 105 3-10 Example No. 16 108 107 3-11 Example No.17 107 110 3-12 Example No. 21 108 111 3-13 Example No. 22 108 110 3-14Comparative No. 156 100 100 example 3-5 Comparative No. 157 101 101example 3-6 Comparative No. 161 100 101 example 3-7 Comparative No. 162100 100 example 3-8 Example No. 1 Graphite 114 118 3-15 (containingExample No. 12 silicon) 113 116 3-16 Example No. 13 108 107 3-17 ExampleNo. 16 111 109 3-18 Example No. 17 111 115 3-19 Example No. 21 112 1163-20 Example No. 22 113 114 3-21 Comparative No. 156 100 100 example 3-9Comparative No. 157 102 102 example 3-10 Comparative No. 161 101 102example 3-11 Comparative No. 162 101 100 example 3-12 Example No. 1 Hardcarbon 113 115 3-22 Example No. 12 111 114 3-23 Example No. 13 107 1063-24 Example No. 16 110 110 3-25 Example No. 17 110 112 3-26 Example No.21 112 113 3-27 Example No. 22 111 111 3-28 Comparative No. 156 100 100example 3-13 Comparative No. 157 101 101 example 3-14 Comparative No.161 100 101 example 3-15 Comparative No. 162 100 100 example 3-16*Relative value in each corresponding battery constitution, when thevalue of Comparative example in which Electrolytic solution No. 156 wasused is designated as 100.

Examples 4-1 to 4-21, and Comparative Examples 4-1 to 4-12

As shown in Table 9, the electrolytic solutions for non-aqueouselectrolyte batteries were prepared, the cells were produced, and theresultant batteries were evaluated in a manner similar to Example 1-1,except that the kinds of the positive electrodes and electrolyticsolutions were varied. In this case, the positive electrode usingLiNi_(0.8)Co_(0.15)Al_(0.05)O₂ as the active material was prepared bymixing 90 mass % of LiNi_(0.8)Co_(0.15)Al_(0.05)O₂ powder with 5 mass %of PVDF as a binder, and 5 mass % of acetylene black as a conductivematerial, further adding N-methylpyrrolidone thereto, applying the thusobtained paste onto an aluminum foil, and then drying the resultantmaterial. When the resultant batteries were evaluated, the end-of-chargevoltage was 4.3 V and the end-of-discharge voltage was 3.0 V.

Moreover, the positive electrode using LiMn₂O₄ as the active materialwas prepared by mixing 90 mass % of LiMn₂O₄ powder with 5 mass % of PVDFas a binder, and 5 mass % of acetylene black as a conductive material,further adding N-methylpyrrolidone thereto, applying the thus obtainedpaste onto an aluminum foil, and then drying the resultant material.When the resultant batteries were evaluated, the end-of-charge voltagewas 4.2 V and the end-of-discharge voltage was 3.0 V.

Furthermore, the positive electrode using LiFePO₄ as the active materialwas prepared by mixing 90 mass % of LiFePO₄ powder coated with amorphouscarbon with 5 mass % of PVDF as a binder, 5 mass % of acetylene black asa conductive material, further adding N-methylpyrrolidone thereto,applying the thus obtained paste onto an aluminum foil, and then dryingthe resultant. When the resultant batteries were evaluated, theend-of-charge voltage was 4.2 V and the end-of-discharge voltage was 2.5V.

The evaluation results are shown in Table 9. In this case, theevaluation results of Examples 4-1 to 4-7 and Comparative examples 4-1to 4-4 are indicated as relative values when the value of Comparativeexample 4-1 is designated as 100. Furthermore, the evaluation results ofExamples 4-8 to 4-14 and Comparative examples 4-5 to 4-8 are indicatedas relative values when the value of Comparative example 4-5 isdesignated as 100. Furthermore, the evaluation results of Examples 4-15to 4-21 and Comparative examples 4-9 to 4-12 are indicated as relativevalues when the value of Comparative example 4-9 is designated as 100.

TABLE 9 Discharge capacity Positive Negative maintenance High powerElectrolytic electrode electrode after capacity solution Active Active200 cycles* maintenance* No. material material [%] [%] Example No. 1LiNi_(0.8)Co_(0.15)Al_(0.05)O₂ Graphite 118 124 4-1 Example No. 12 117122 4-2 Example No. 13 111 110 4-3 Example No. 16 117 115 4-4 ExampleNo. 17 114 121 4-5 Example No. 21 114 123 4-6 Example No. 22 115 119 4-7Comparative No. 156 100 100 example 4-1 Comparative No. 157 101 102example 4-2 Comparative No. 161 101 101 example 4-3 Comparative No. 162100 100 example 4-4 Example No. 1 LiMn₂O₄ Graphite 121 129 4-8 ExampleNo. 12 118 127 4-9 Example No. 13 115 112 4-10 Example No. 16 118 1184-11 Example No. 17 117 125 4-12 Example No. 21 119 125 4-13 Example No.22 120 121 4-14 Comparative No. 156 100 100 example 4-5 Comparative No.157 102 103 example 4-6 Comparative No. 161 102 102 example 4-7Comparative No. 162 100 101 example 4-8 Example No. 1 LiFePO₄ Graphite112 114 4-15 Example No. 12 107 113 4-16 Example No. 13 105 105 4-17Example No. 16 107 108 4-18 Example No. 17 107 110 4-19 Example No. 21109 110 4-20 Example No. 22 109 108 4-21 Comparative No. 156 100 100example 4-9 Comparative No. 157 101 101 example 4-10 Comparative No. 161100 101 example 4-11 Comparative No. 162 100 100 example 4-12 *Relativevalue in each corresponding battery constitution, when the value ofComparative example in which Electrolytic solution No. 156 was used isdesignated as 100.

It was confirmed from the results in Table 7 to Table 9 that, regardlessof the kinds of the active materials of negative electrodes or theactive materials of positive electrodes, the addition of the above saltshaving the divalent imide anions into the electrolytic solutionsprovides a good high-temperature cycle characteristic and a goodlow-temperature output characteristic and the effects similar to theabove were obtained, when the electrolytic solutions were used innon-aqueous electrolyte batteries.

Example 5-1

With the use of a mixed solvent of ethylene carbonate and diethylcarbonate at a volume ratio of 1:1 as a non-aqueous solvent, NaPF₆ wasdissolved as a solute to a concentration of 1.0 mol/L, and the disodiumsalt of the above Compound No. 1 as a salt having an imide anion wasdissolved to a concentration of 0.1 mass % into the solvent. Theelectrolytic solutions for non-aqueous electrolyte batteries wereprepared as shown in Table 10. In this case, the above preparation wasperformed while maintaining the liquid temperature at 25° C.

The cells were produced using the electrolytic solutions in a mannersimilar to Example 1-1, except that NaFe_(0.5)Co_(0.5)O₂ was used as apositive electrode material and hard carbon was used as a negativeelectrode material. The resultant batteries were evaluated in a mannersimilar to Example 1-1. In this case, the positive electrode usingNaFe_(0.5)Co_(0.5)O₂ as the active material was prepared by mixing 90mass % of NaFe_(0.5)CO_(0.6)O₂ powder, 5 mass % of PVDF as a binder, and5 mass % of acetylene black as a conductive material, further addingN-methylpyrrolidone thereto, applying the thus obtained paste onto analuminum foil, and then drying the resultant. When the resultantbatteries were evaluated, the end-of-charge voltage was 3.8 V and theend-of-discharge voltage was 1.5 V. The evaluation results are shown inTable 11.

Examples 5-2 to 5-14, and Comparative Examples 5-1 to 5-5

As shown in Table 10, the electrolytic solutions for non-aqueouselectrolyte batteries were prepared in a manner similar to Example 5-1,except that the kinds and concentrations of the solutes, and the kindsand concentrations of the salts having the imide anions were varied, thecells were produced, and then the resultant batteries were evaluated.The evaluation results are shown in Table 11. In addition, theevaluation results of Examples 5-1 to 5-14, and Comparative examples 5-1to 5-5 are indicated as relative values when the value of comparativeexample 5-1 is designated as 100.

TABLE 10 Solute 1 Solute 2 Salt having imide anion ConcentrationConcentration Compound Counter Concentration Kind [mol/L] Kind [mol/L]No. cation [mass %] Electrolytic NaPF₆ 1.0 None 0 No. 1 2Na⁺ 0.1solution No. 173 Electrolytic No. 6 0.1 solution No. 174 ElectrolyticNo. 7 0.1 solution No. 175 Electrolytic No. 10 0.1 solution No. 176Electrolytic No. 11 0.1 solution No. 177 Electrolytic No. 15 0.1solution No. 178 Electrolytic No. 16 0.1 solution No. 179 ElectrolyticNaPF₄(C₂O₄) 0.1 No. 1 2Na⁺ 0.1 solution No. 180 Electrolytic 0.1 No. 60.1 solution No. 181 Electrolytic 0.1 No. 7 0.1 solution No. 182Electrolytic 0.1 No. 10 0.1 solution No. 183 Electrolytic 0.1 No. 11 0.1solution No. 184 Electrolytic 0.1 No. 15 0.1 solution No. 185Electrolytic 0.1 No. 16 0.1 solution No. 186 Electrolytic None 0 None —0 solution No. 187 Electrolytic No. 19 Na⁺ 0.1 solution No. 188Electrolytic No. 23 0.1 solution No. 189 Electrolytic No. 24 0.1solution No. 190 Electrolytic NaPF₄(C₂O₄) 0.1 None — 0 solution No. 191

TABLE 11 Discharge capacity Positive Negative maintenance High powerElectrolytic electrode electrode after capacity solution Active Active200 cycles* maintenance* No. material material [%] [%] Example No. 173NaFe_(0.5)Co_(0.5)O₂ Hard carbon 109 110 5-1 Example No. 174 106 108 5-2Example No. 175 103 104 5-3 Example No. 176 105 107 5-4 Example No. 177105 109 5-5 Example No. 178 106 110 5-6 Example No. 179 107 108 5-7Example No. 180 119 116 5-8 Example No. 181 117 114 5-9 Example No. 182113 110 5-10 Example No. 183 116 114 5-11 Example No. 184 117 115 5-12Example No. 185 117 116 5-13 Example No. 186 118 114 5-14 ComparativeNo. 187 100 100 example 5-1 Comparative No. 188 102 102 example 5-2Comparative No. 189 101 101 example 5-3 Comparative No. 190 101 100example 5-4 Comparative No. 191 111 106 example 5-5 *Relative value whenthe result of Comparative example 5-1 is designated as 100.

It was confirmed from the results in Table 11 that even in the case ofsodium ion batteries, both a high-temperature cycle characteristic and alow-temperature output characteristic were improved in Examples 5-1 to5-7 in which the above salts having divalent imide anions were added tothe electrolytic solutions, as compared with Comparative example 5-1 inwhich no such salt was added.

It was similarly confirmed that a high-temperature cycle characteristicand a low-temperature output characteristic were improved in Examples5-1 to 5-7 in which the salts having the divalent imide anions of thepresent invention were contained at the same concentration (0.1 mass %),as compared with Comparative examples 5-2 to 5-4 in which salts havingmonovalent imide anions were used.

Furthermore, it was confirmed that also in the case of sodium ionbatteries, the use of the salt having an imide anion with a P—F bond oran S—F bond provides a better low-temperature output characteristic. Itwas also confirmed that the higher the number of P—F bonds or S—F bondsin the above salts having imide anions, the more the low-temperaturecharacteristic is improved.

Furthermore, it was confirmed that the use of the salt having a divalentimide anion wherein R¹ to R³ in the general formula (1) or (3) are afluorine atom or an organic group selected from the group consisting ofan alkenyloxy group and an alkynyloxy group provides a betterhigh-temperature cycle characteristic.

Furthermore, it was confirmed that the use of the salt having a divalentimide anion wherein X in the general formula (2) or (4) is a fluorineatom or an organic group selected from the group consisting of an alkoxygroup, an alkenyloxy group, and an alkynyloxy group provides a betterhigh-temperature cycle characteristic.

Furthermore, it was confirmed that also in the case of mixing NaPF₆ withanother solute, a high-temperature cycle characteristic and alow-temperature output characteristic were improved in Examples 5-8 to5-14 in which the salts having divalent imide anions were added, ascompared with Comparative example 5-5 in which no such salt having adivalent imide anion was added, and accordingly the similar effects wereobtained.

1. An electrolytic solution for a non-aqueous electrolyte battery,comprising a non-aqueous solvent, a solute, and at least one salt havinga divalent imide anion represented by any one of the following generalformulae (1) to (4).

[In formulae (1) to (3), R¹ to R³ each independently represent afluorine atom or an organic group selected from a linear or branchedC1-10 alkoxy group, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group,a C3-10 cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10aryloxy group, wherein a fluorine atom, an oxygen atom or an unsaturatedbond may also be present in the organic group; In formulae (2) and (4),X represents a fluorine atom or an organic group selected from a linearor branched C1-10 alkyl group, a C2-10 alkenyl group, a C2-10 alkynylgroup, a C3-10 cycloalkyl group, a C3-10 cycloalkenyl group, a C6-10aryl group, a linear or branched C1-10 alkoxy group, a C2-10 alkenyloxygroup, a C2-10 alkynyloxy group, a C3-10 cycloalkoxy group, a C3-10cycloalkenyloxy group and a C6-10 aryloxy group, wherein a fluorineatom, an oxygen atom, or an unsaturated bond may also be present in theorganic group; and M¹ and M² each independently represent a proton, ametal cation or an onium cation.]
 2. The electrolytic solution accordingto claim 1, wherein said salt has at least one P—F bond or S—F bond. 3.The electrolytic solution according to claim 1, wherein said R¹ to R³represent a fluorine atom or an organic group selected from the groupconsisting of a C2-10 alkenyloxy group and a C2-10 alkynyloxy group. 4.The electrolytic solution according to claim 3, wherein said alkenyloxygroup is selected from the group consisting of a 1-propenyloxy group, a2-propenyloxy group, and a 3-butenyloxy group, and said alkynyloxy groupis selected from the group consisting of a 2-propynyloxy group, and1,1-dimethyl-2-propynyloxy group.
 5. The electrolytic solution accordingto claim 1, wherein said X is a fluorine atom or an organic groupselected from the group consisting of a C1-10 alkoxy group, a C2-10alkenyloxy group and a C2-10 alkynyloxy group.
 6. The electrolyticsolution according to claim 5, wherein said alkoxy group is selectedfrom the group consisting of a methoxy group, an ethoxy group and apropoxy group; said alkenyloxy group is selected from the groupconsisting of a 1-propenyloxy group, a 2-propenyloxy group and a3-butenyloxy group; and said alkynyloxy group is selected from the groupconsisting of a 2-propynyloxy group and a 1,1-dimethyl-2-propynyloxygroup.
 7. The electrolytic solution according to claim 1, wherein thecounter cations M¹ and M² of the imide anion in said salt represent atleast one cation selected from the group consisting of a proton, alithium ion, a sodium ion, a potassium ion, a tetraalkylammonium ion,and a tetraalkylphosphonium ion.
 8. The electrolytic solution accordingto claim 7, wherein the concentration of said salt ranges from 0.01 to5.0 mass % relative to the total amount of the electrolytic solution. 9.The electrolytic solution according to claim 8, wherein said solute isat least one solute selected from the group consisting of LiPF₆,LiPF₂(C₂O₄)₂, LiPF₄(C₂O₄), LiP(C₂O₄)₃, LiBF₂(C₂O₄), LiB(C₂O₄)₂, LiPO₂F₂,LiN(F₂PO)₂, LiN(FSO₂)₂, LiN(CF₃SO₂)₂, LiBF₄, NaPF₆, NaPF₂(C₂O₄)₂,NaPF₄(C₂O₄), NaP(C₂O₄)₃, NaBF₂(C₂O₄), NaB(C₂O₄)₂, NaPO₂F₂, NaN(F₂PO)₂,NaN(FSO₂)₂, NaN(CF₃SO₂)₂ and NaBF₄.
 10. The electrolytic solutionaccording to claim 9, wherein said non-aqueous solvent is at least onenon-aqueous solvent selected from the group consisting of a cycliccarbonate, a linear carbonate, a cyclic ester, a linear ester, a cyclicether, a linear ether, a sulfone compound, a sulfoxide compound and anionic liquid.
 11. A non-aqueous electrolyte battery comprising at leasta positive electrode, a negative electrode, and the electrolyticsolution for a non-aqueous electrolyte battery according to claim 1.